Film printing system and method utilizing a digital light processing imager or organic light emitting diode

ABSTRACT

A motion picture printing system having a digital micromirror device for manipulating light used to expose a film negative is disclosed. A motion picture printing system having an organic light emitting diode for emitting light to expose a film negative is disclosed.

FIELD OF THE INVENTION

The invention relates to film printing technology for use with a digitallight processing imager (DLP) or an organic light emitting diode (OLED).

BACKGROUND OF THE INVENTION

Continuous contact film printing systems are known and have beenutilized in the motion picture industry. In its simplest form,continuous contact printing consists of exposing a raw stock of filmfrom an original or printing master to form an image ‘using a lightsource to produce the exposure. A schematic diagram of such a system isshown in FIG. 1 and will now be described. In the film printing system10 shown here, a raw stock of film 12 is fed from a first feed reel 1 toa first take up reel 2. The reels 1 and 2 are driven by correspondingmotors, M₁ and M₂. In between reels 1 and 2, the raw stock of film 12 ispassed over a picture encoder E₁ and then a sound encoder E₂. Turningfirst to the picture encoder E₁, a light source, well-known as a lightbox 20 is coupled to a printing head 40 for exposing the raw stock offilm 12 from an original 14 (positive film or master film) which issimultaneously fed from reel 3 to reel 4. Reels 3 and 4 are driven bycorresponding motors M₃ and M₄. Light passes from the light box 20,through the print head 40, then through the original 14 to expose theraw stock of film 12, effectively transferring the image data containedon the original 14 to the raw stock of film 12. Since the light box 20is well known in the industry, a detailed description will not beprovided here. However, briefly, the light box 20 contains colorseparating optics, gates for controlling the color spectrum, collimatingoptics, and focusing optics at the output to printing head 40. Theprinting head 40 receives light from the focusing optics at the outputof the light box 20 onto a folding mirror 42 which reflects the incidentlight through anamorphic optics 44. Light then passes from theanamorphic optics 44 through a film printing aperture 46 exposing theraw stock of film 12 through the original 14. Sound is then encoded ontothe film 12 at the sound encoder E₂ utilizing known techniques whichwill not be described in further detail here.

Creating motion pictures for use in foreign markets requires subtitlingto be applied during the film printing process. Application of thesubtitles is known as a form of post production. Generally, in order tosubtitle a film, a first original carrying the images and a secondoriginal carrying the subtitling or text are superimposed onto eachother. In utilizing the known process described above to transfer theimages and the subtitling to a single raw stock, a continuous contactfilm printing system is configured to allow the two originals to besimultaneously carried on reels 3 and 4 over the printing head 40.Because two originals are required, postproduction is cumbersome andcostly. Additionally, the use of two originals in printing may hinderthe ultimate picture quality of the printed film. Further, the abovedescribed process must be repeated for each separate language the filmis to be subtitled, representing significant costs of time and labor.While it has been contemplated to use an LCD or and LCoS device to aidin the printing of images to film negative 12, these device tend to havelow refresh rates (possibly slowing the printing process), lowercontrast ratios, and are primarily electrical in construction (leadingto high maintenance costs). It is therefore desirable to develop animproved system for printing the subtitle text onto the film 12.

SUMMARY OF THE INVENTION

The present invention is directed to an improved apparatus for printingsubtitle text onto film.

An object of the present invention is to provide a system for and methodof printing of subtitles onto raw film stock without the need for anoriginal which carries the subtitles. The present invention satisfiesthis object by providing a film printing system comprising a DLP imagerfor transmitting subtitles through a positive or master film and onto anegative film stock.

Another object of the present invention is to provide a system for andmethod of directly printing subtitles to raw film stock without the needfor an original master film or an original which carries subtitles. Thepresent invention satisfies this object by providing a film printingsystem comprising a DLP imager for transmitting both, the motion pictureimage data and any optional subtitles, directly onto a negative filmstock. The present invention further satisfies this object by providinga film printing system comprising an OLED device for transmitting both,the motion picture image data and any optional subtitles, directly ontoa negative film stock.

The present invention offers at least the following advantages: offeringhigh refresh rates (speeding up the printing process), higher contrastratios, and inexpensive mechanical components (lowering maintenancecosts).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a known continuous contact filmprinting system;

FIG. 2A is a schematic illustration of a film printing system accordingto a first embodiment of the present invention;

FIG. 2B is an enlarged schematic illustration of a portion of the filmprinting system of FIG. 2A;

FIG. 3A is a front view of an example negative film frame output fromthe film printing system of FIG. 2;

FIG. 3B is a front view of another example negative film frame outputfrom the film printing system of FIG. 2;

FIG. 4 is a schematic view of a printing system according to a secondembodiment of the present invention;

FIG. 5 is a schematic view of a printing system according to a thirdembodiment of the present invention;

FIG. 6 is a schematic view of a printing system according to a fourthembodiment of the present invention;

FIG. 7 is a schematic view of a printing system according to a fifthembodiment of the present invention; and

FIG. 8 is a schematic view of a printing system according to a sixthembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2A shows a film printing system according to a first embodiment ofthe present invention. Film printing system 100 is substantially similarto prior art film printing system 10 but with the prior art printinghead 40 being replaced by a DLP printing head 102 according to thepresent invention. Similar to printing head 40, printing head 102receives light from the focusing optics at the output of the light box20. FIG. 2B shows an enlarged view of printing head 102 and the lightbox 20. (As shown, light box 20 is a known device which, through the useof dichroic mirrors, reflectors, light valves or gates, and otheroptical components, is capable of regulating the relative output ofadditive color components, red, green, and blue. When used in contactprinting, light box 20 is typically controlled to supply high qualityfull spectrum or white light.) The output of the light box 20 passesthrough an output lens 104 and is directed into a total internalreflection lens 106 (TIR lens) which is well known in the art assuitable for receiving light, directing the received light to a digitalmicromirror device (DMD), commonly referred to as digital lightprocessor imager (DLP imager), and finally outputting the lightaccording to an image signal of the DLP imager. In an alternativeembodiment, the TIR lens 106 may be replaced by a field lens. Uponentering the TIR lens 106, light is reflected to an opticalsemiconductor of a suitable “single-chip” DLP imager 108 (having aresolution of approximately 2000×1000). However, it will be appreciatedthat alternative embodiments of the present invention may besubstantially similar to film printing system 100, but comprising a“three-chip” DLP imager rather than the “single-chip” DLP imager.Providing a three-chip DLP imager would provide optimal performance andwould eliminate any problems with so-called “rainbow effects” and/ortime sequential color effects sometimes resulting from the use of asingle-chip DLP imager.

DLP imagers are well known and comprise an optical semiconductor (notshown). The semiconductor (not shown) contains an array of hinge-mountedmicroscopic mirrors. Each of the mirrors corresponds to one pixel in animage (not shown) of the input signal. When the semiconductor (notshown) is driven by the controller based on the input signal, themirrors are individually tilted or switched on or off to selectivelyreflect light either toward an output path of the TIR lens 106 or awayfrom the output path of the TIR lens 106, possibly toward a lightabsorption device (not shown). An array of pixels reflected from theswitched mirrors forms a projected light matrix corresponding to aninput signal from a display controller. The display controller (notshown) of the present invention directs the mirrors to reflect lightsuch that the light matrix carries appropriate pixel combinations fortransmitting subtitles from the TIR lens 106 and into a system oftelecentric optics 110 which replace the anamorphic optics 44 of FIG. 1.In order to provide selective coloring of the light matrix, it is wellknown that prior to reaching the minors of the DLP imager, the whitelight is passed through a so-called color wheel filter, causing red,green and blue light to be shone in sequence on the minors. Theswitching of the minors and the proportion of time the mirrors are ‘on’or ‘off’ is coordinated according to the color shining on them such thatthe human visual system integrates the sequential color and sees afull-color image. All of the required color coordination is inherentlypresent in the input signal from the display controller.

The telecentric optics 110 direct the projected light matrix through afilm printing aperture 46, through a positive film (or master film) 14,and onto a raw stock of film 12 (negative film), effectively exposingthe raw stock of film such that the negative carries the master filmcontents and subtitling.

Referring now to FIGS. 3A and 3B, the result of this process is theappearance of subtitling text 112 on the frames 114 of the newly exposednegative film 12. The text 112 corresponds to the input signal and canbe written with a tombstone 116, a border surrounding the text (see FIG.3B), or without a tombstone (see FIG. 3A). It will be appreciated thatalternative embodiments of the present invention may include inputsignals from the display controller containing graphical content otherthan simple subtitling. For example, the input signal may includescrolling credits, titles, or any other shape or indicia capable ofbeing transmitted to the DLP imager by the display controller.

Referring now to FIG. 4, a film printing system according to a secondembodiment of the present invention is illustrated. While the single DLPimager 108 (having a resolution of approximately 2000×1000) of filmprinting system 100 described above is sufficient for creatingacceptable subtitles, the resolution of DLP imager 108 is not sufficientfor generating acceptable motion picture images over an entire imageframe. Film printing system 200 is substantially similar to filmprinting system 100, but with a few major differences. A firstdifference is that the single-chip DLP imager 202 of film printingsystem 200 has a higher resolution than that of DLP imager 108. Morespecifically, the DLP imager 202 has a resolution of approximately4000×2000 (not yet commercially available), which is considered asuitable resolution for accurately reproducing the motion picture imagescarried on a positive film (or master film). Due to this increasedresolution, the printing process associated with film printing system100 may be simplified. Namely, film printing system 200 provides forprinting motion picture images and optional subtitling (or any othergraphics) directly onto a film negative 12 without the use of a positiveor master film 14. Since a positive or master film 14 is not used insystem 200, there is no need for reels 3,4 and motors M₃, M₄, therefore,they are not represented in FIG. 4. Operation of film printing system200 is similar to operation of film printing system 100, but in filmprinting system 200, no positive or master film is used. Rather, theinput signal of DLP imager 202 transmitted to the mirrors (not shown) ofDLP imager 202 by the display controller of DLP imager 202 (not shown)contains all image data related to both the motion picture and anysubtitling and/or other optional graphics. It will be appreciated thatalternative embodiments of the present invention may be substantiallysimilar to film printing system 200, but comprising a “three-chip” DLPimager rather than the “single-chip” DLP imager. Providing a three-chipDLP imager would provide optimal performance and would eliminate anyproblems with so-called “rainbow effects” and/or time sequential coloreffects sometimes resulting from the use of a single-chip DLP imager.

Referring now to FIG. 5, a film printing system according to a thirdembodiment of the present invention is illustrated. It is currentlythought that a DLP imager having resolution of about 2000×1000 isinsufficient for accurately reproducing an entire frame of motionpicture image data onto a negative film frame, thereby eliminating DLPimagers with resolution of about 2000×1000 from use as an accepted meansfor directly printing onto negative film frames without the use of apositive or master film. However, film printing system 300advantageously utilizes a plurality of commercially available DLPimagers (having resolution of about 2000×1000) to accomplish a resultsimilar to that of film printing system 200 where negative film framesare exposed with images solely emanating from DLP imagers, without theuse of positive or master film. To accomplish this, the entire frame 302of a target negative film 304 is divided into four regions, an upperleft region 306, a lower left region 308, an upper right region 310, anda lower right region 312. Region 306 is to be directly printed onto byDLP imager 314, region 308 is to be directly printed onto by DLP imager316, region 310 is to be directly printed onto by DLP imager 318, andregion 312 is to be directly printed onto by DLP imager 320. Each DLPimager 314, 316, 318, and 320 is substantially similar to DLP imager108, but instead of each DLP imager 314, 316, 318, and 320 having acolor wheel filter, a single color wheel filter 322 is used. Inoperation, white light or full spectrum light is emitted from a lightsource 324 and is directed through the spinning color wheel filter 322,possibly with guidance from an elliptical reflector 325. Since each DLPimager 314, 316, 318, and 320 must be supplied with light, the lightexiting the spinning color wheel filter 322 is separated into fourchannels of light (ideally identical in intensity and color) through theuse of light beam splitting prisms. A first light beam splitting prism326 splits the original light beam 328 into two new light beams 330 and332. Light beam 330 is directed from prism 326 into a second light beamsplitting prism 334, resulting in light beams 336 and 338. Light beam332 is directed from prism 326 into a third light beam splitting prism340, resulting in light beams 342 and 344. Each of light beams 336, 338,342, and 344 are directed into and delivered through optical fibers 346to TIR lenses 348 associated with DLP imagers 314, 316, 318, and 320,respectively. TIR lenses 348 operate in substantially the same manner asTIR lens 106 with respect to delivering light from fibers 346 to DLPimagers 314, 316, 318, and 320. However, TIR lenses 348 are oriented todirect their output into an arrangement of reflective prisms 350 andoptical blocks 352 so as to forward the four light beams 336, 338, 342,and 344 (or channels of light) (as altered by DLP imagers 314, 316, 318,and 320) into a telecentric optics system 354. Telecentric optics system354 ultimately directs the light beams 336, 338, 342, and 344 ontoregions 306, 308, 310, and 312, respectively, of the entire frame 302 ofa target negative film 304. Of course, the input signals sent fromdisplay controllers of DLP imagers 314, 316, 318, and 320 to the mirrorsof the respective DLP imagers comprise only the data necessary to createthe desired image to be printed in the associated regions of frame 302.In an alternative embodiment, telecentric optics system 354 could bereplaced by a projection optics system and the resulting output could bea projected image on a reflective screen or other surface, allowing forreal-time superimposing of subtitles and/or other graphics in theprojected image. It will be appreciated that in other embodiments of thepresent invention, more or fewer DLP imagers may be incorporated toachieve a higher or lower overall film frame resolution, respectively.

Referring now to FIG. 6, a film printing system according to a fourthembodiment of the present invention is illustrated. Film printing system400 is substantially similar to film printing system 200, but with a fewmajor differences. First, film printing system 400 incorporates anorganic light emitting diode display device 402 (an OLED) rather than aDLP imager such as DLP imager 108 as a means for generating subtitlesand/or motion picture image data. Second, since OLED devices inherentlyactively emit illumination, there is no need for a light box 20 toprovide white light for subsequent filtering and reflection as needed byDLP imagers. Since a positive or master film 14 is not used in system200, there is no need for reels 3,4 and motors M₃, M₄, therefore, theyare not represented in FIG. 6. Finally, as the OLED device 402 iscapable of emitting light from a substantially constant distance from afilm printing aperture 46, there is no need for expensive and sizabletelecentric optics such as telecentric optics system 354.

Referring now to FIG. 7, a film printing system according to a fifthembodiment of the present invention is illustrated. Film printing system500 is substantially similar to film printing system 400, but with a fewmajor differences. In film printing system 500, an OLED device 502 isprovided with the necessary data for displaying and projecting ontonegative 12 the entire frame image, including the sound information.Now, OLED device 502 alone can optically transfer all of the contents tonegative 12 which are necessary for producing a finished negative 12.Furthermore, since sound is now transferred to the negative by OLEDdevice 502, there is no need for a separately located sound encoder E₂,but rather, the OLED device 502 serves as both the picture encoder E₁and the sound encoder E₂. Consequently, there is no need for reels 5, 6and motors M₅, M₆, therefore, they are not represented in FIG. 7. Amajor advantage of printing sound and video at the same time is thatsound and video synchronization is accomplished.

Referring now to FIG. 8, a film printing system according to a sixthembodiment of the present invention is illustrated. Film printing system600 is substantially similar to film printing system 500, but with a fewmajor differences. In film printing system 600, a three-chip DLP imager602 (instead of an OLED device 502) is provided with the necessary datafor displaying and projecting onto negative 12 the entire frame image,including the sound information. Now, DLP imager 602 alone can opticallytransfer all of the contents to negative 12 which are necessary forproducing a finished negative 12. Furthermore, since sound is nowtransferred to the negative by DLP imager 602, there is no need for aseparately located sound encoder E₂, but rather, the DLP imager 602serves as both the picture encoder E₁ and the sound encoder E₂.Consequently, there is no need for reels 5, 6 and motors M₅, M₆,therefore, they are not represented in FIG. 8. Another differencebetween system 600 and system 500 is that since a DLP imager is beingutilized, light box 20 is needed and is. therefore represented in FIG.8. A major advantage of printing sound and video at the same time isthat sound and video synchronization is accomplished.

The foregoing illustrates only some of the possibilities for practicingthe invention. Many other embodiments are possible within the scope andspirit of the invention. It is, therefore, intended that the foregoingdescription be regarded as illustrative rather than limiting, and thatthe scope of the invention is given by the appended claims together withtheir full range of equivalents.

1. A film printing system, the film printing system comprising: a light box for generating and emitting light; and a printing head having a digital micromirror device configured to receive and selectively manipulate the light emitted by the light box and configured to reflect the manipulated light through a film printing aperture of the printing head.
 2. The film printing system according to claim 1, further comprising: a TIR lens optically disposed between the light box and the digital micromirror device and also optically disposed between the digital micromirror device and the film printing aperture.
 3. The film printing system according to claim 2, further comprising: a telecentric optics system optically disposed between the TIR lens and the film printing aperture.
 4. The film printing system according to claim 1, wherein the digital micromirror device, in response to an input signal, manipulates light to carry subtitle data.
 5. The film printing system according to claim 1, wherein the digital micromirror device, in response to an input signal, manipulates light to carry a full frame of motion picture image data.
 6. The film printing system according to claim 1, further comprising: a light beam splitter for splitting the light emitted from the light box into a plurality of separate beams of light; a plurality of digital micromirror devices, each adapted to receive a single beam of light of the plurality of separate beams of light; wherein each of the digital micromirror devices is adapted to manipulate a received beam of light to carry motion picture image data corresponding to only a discrete portion of an entire image frame.
 7. A film printing system, the film printing system comprising: an organic light emitting diode display device configured to emit light corresponding to motion picture image data and configured to emit the light through a film printing aperture and onto a film negative.
 8. A method of film printing, comprising the steps of: manipulating light with a digital micromirror device; directing the manipulated light through a film printing aperture; and directing the manipulated light onto a film negative.
 9. The method of film printing according to claim 8, further comprising the step of: directing the manipulated light through a film positive prior to directing the manipulated light onto the film negative.
 10. The method of film printing according to claim 8, wherein the light is manipulated to carry subtitle data.
 11. The method of film printing according to claim 8, wherein the light is manipulated to carry motion picture image data.
 12. The method of film printing according to claim 8, further comprising the step of: directing the manipulated light through a telecentric optical system prior to directing the manipulated light through the film printing aperture. 